Hello,
I have started to notice a knocking sound when I turn the AC on...the AC works fine and blows cold...and the car seems to run as expected but I'm just wondering if this knocking sound is a sign that something is about to go out. Any ideas??
Thanks.

 

it sounds like the compressor is switching on and off

 

My maxima is making a pinging sound on the outside of the car with the AC on. but when i turn it off, it stops. I have a feeling that it is because of a fan or something.

 

Yeah, if it's a "pinging/clicking sound," it's just the magnetic clutch engaging/disengaging from the A/C compressor- it's normal if that's what you described.

 

Yeah, thats what mine is I guess.

 

is it knocking or clicking?